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Literature summary for 6.1.1.4 extracted from

  • Pang, Y.L.; Martinis, S.A.
    A paradigm shift for the amino acid editing mechanism of human cytoplasmic leucyl-tRNA synthetase (2009), Biochemistry, 48, 8958-8964.
    View publication on PubMedView publication on EuropePMC

Protein Variants

Protein Variants Comment Organism
D399A 40fold increase in Km for leucine activation. Mutation eliminates Ile-tRNALeu deacylation activity Homo sapiens
T298A activity similar to wild-type, mutation maintains Ile-tRNALeu deacylation activity Homo sapiens
T298Y mutation uncouples specificity in the editing active site and mutant hydrolyzes Leu-tRNALeu Homo sapiens

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.024
-
L-leucine wild-type, pH 7.6, 30°C Homo sapiens
0.9
-
L-leucine mutant D399A, pH 7.6, 30°C Homo sapiens
2.04
-
L-isoleucine wild-type, pH 7.6, 30°C Homo sapiens
3.3
-
L-isoleucine mutant D399A, pH 7.6, 30°C Homo sapiens

Localization

Localization Comment Organism GeneOntology No. Textmining
cytoplasm
-
Homo sapiens 5737
-

Organism

Organism UniProt Comment Textmining
Homo sapiens Q9P2J5
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
ATP + L-isoleucine + tRNALeu
-
Homo sapiens AMP + diphosphate + L-isoleucyl-tRNALeu
-
?
ATP + L-leucine + tRNALeu
-
Homo sapiens AMP + diphosphate + L-leucyl-tRNALeu
-
?
L-isoleucyl-tRNALeu + H2O
-
Homo sapiens t-RNALeu + L-isoleucine editing activity ?

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.34
-
L-isoleucine wild-type, pH 7.6, 30°C Homo sapiens
0.51
-
L-isoleucine mutant D399A, pH 7.6, 30°C Homo sapiens
2.1
-
L-leucine wild-type, pH 7.6, 30°C Homo sapiens
5.6
-
L-leucine mutant D399A, pH 7.6, 30°C Homo sapiens

kcat/KM [mM/s]

kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
0.16
-
L-isoleucine wild-type, pH 7.6, 30°C Homo sapiens
0.17
-
L-isoleucine mutant D399A, pH 7.6, 30°C Homo sapiens
5.6
-
L-leucine mutant D399A, pH 7.6, 30°C Homo sapiens
94.3
-
L-leucine wild-type, pH 7.6, 30°C Homo sapiens